As a related-art interior permanent magnet motor, in Patent Literature 1, there is disclosed an interior permanent magnet motor having a plurality of slits formed in a rotor at a radially outer side with respect to each of magnet insertion holes. In the interior permanent magnet motor, it is expected that a harmonic component of a magnetic-flux density waveform is reduced due to a function of the slits so that a harmonic of an inducted voltage and a cogging torque are reduced, thereby reducing noise and vibration.